These units don’t appear to have much in common. If you’re replacing one with the other, you’ll need to make some modifications to wall, unit or something in between with a plate or adapter curb.
| Match | Marvair ECUA18 | Marvair ECUA12 | Difference |
|---|---|---|---|
| Unit width | 18" | 18.25" | +0.25" |
| Unit height | 58.125" | 58" | -0.125" |
| Return Air | 13.25" x 5" | 13.25" x 5" | 0" |
| Distance from the top to Supply | 20.688" | 20.875" | +0.187" |
| Distance between Supply and Return | 19.062" | 19.25" | +0.188" |
| Distance from Return to bottom | 1.25" | 1.125" | -0.125" |
| Mismatch | Marvair ECUA18 | Marvair ECUA12 | Difference |
|---|---|---|---|
| Unit depth | 18.063" | 12" | -6.063" |
| Unit weight | 247 lbs | 160 lbs | -87 lbs |
| Supply Air | 14.688" x 12.125" | 14.375" x 11.75" | -0.313" x -0.375" |